It's a longshot that anyone would want to buy a Note 7 now, but if you do then it's going to be tough to find a store that'll sell you one.
It was just last week that the U.S. carriers started voluntarily taking in Note 7s for return despite having just issued hundreds of thousands as recall replacements. Now T-Mobile, Verizon, Sprint, AT&T, U.S. Cellular and Best Buy have halted exchanges and completely stopped selling the much-maligned Note 7 to new customers as well.
Sales halted, and they probably aren't going to resume.
Each of the retailers' websites show the phone as out of stock, unavailable or completely missing, and statements from each carrier have expressed to Android Central that the phone is no longer on sale citing safety concerns. A common theme among the statements is that customers who purchased a Note 7 or exchanged for a new model have options to return their phone with no penalty to the carrier or store they purchased from.
Chances are at this point that the U.S. carriers will not have the Note 7 for sale again in the future, considering the constant headache this situation has caused them. Samsung, for its part, has said it is simply "adjusting" its production schedule for the phones, but it's not hard to see that moving to a complete halt soon.